Transcript ACES-Power-existing

Power Distribution
Existing Systems
Power in the trackers
Power in the calorimeters
Need for changes
Introduction
Similar power needs for the ATLAS & CMS trackers
and for the ATLAS & CMS calorimeters
CMS
Tracker
ATLAS
Power
Current
Pixel
3 kW
1.5 kA
Si Strips
31 kW
15 kA
116 kW
46 kA
EM Calorimeters ECAL
Pixel
Si Strips
TRT
Larg*
Power
Current
6 kW
18 kW
22 kW
140 kW
3.7 kA
6 kA
6.5 kA
27 kA
* Including the hadronic end-cap
Power dissipated by the front-end electronics
However different solutions have been implemented
Useful to look at them and see whether they could
be used for SLHC
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
2
ATLAS & CMS Silicon Strips
Same concept:
Regulated power supplies out of the detectors
One per detector module in ATLAS (4088 modules)
In the control rooms  > 100-m cables
4 power lines (4 V, 3.5 V, opto devices)
One per group of modules in CMS (1944 groups)
In the experimental cavern  45-m cables
2 power lines (2.5 V and 1.25 V)
Advantages:
No need for power devices inside the detector volume
No extra power in the detector volume
Very good control of the current returns
Disadvantages:
Large amount of cables and power supplies modules
Trade-off power loss – material budget
Regulation loop of the PS includes long cables
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
3
Power Cables: CMS Strips
Detector volume
“Balconies”
~ 40 m
Tracker
“Patch
Panel 1”
~5m
Tracker
structures
PSU Crates
~ 40 m of Cu “Low
Impedance Cable” (LIC)
~ 5 m of Aluminum
“Multi Service Cable”
(MSC)
- MATERIAL BUDGET -
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
4
Power Cables: ATLAS Strips
PS RACK (22)
EARTH TIE Near PP3
48 VDC POWER PACK
PP3 (4088)
COMMON MODE CHOKES
VOLTAGE LIMITER
PS CRATE (4)
PS CRATE
C
C
TYPE III CABLE
DCS VIA
CANbus
PP2
Factory SPLICE
TYPE IV CABLE
DETECTOR
MODULE
(4088)
LOW MASS
POWER TAPE
PPF0
END-CAP ONLY
TYPE II CABLE
LOW MASS
POWER TAPE
PPB1 or
PPF1
SINGLE POINT EARTH
3 Types of cables outside the tracker volume
Low mass tapes in the tracker volume
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
5
Cables…
The beauty
ATLAS Barrel SCT
Ph. Farthouat
The beast
(from Allan Clark)
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
6
Voltage Drop & Power Loss
CMS
Tracker
Similar for both detectors:
As much power dissipated in the cable as in the electronics for
nominal conditions
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
7
Can it be used for SLHC?
Number of channels and modules x10
No way to have one PS channel per module
Material budget cannot be increased
 no extra material for cables
 very likely more current per Cu mm2
Power / channel reduced but Vdd as well
 more power loss and more cooling needs
Not very attractive
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
8
Use of Voltage Regulators
CMS Pixel (regulators in Read-Out Chip),
CMS ECAL, ATLAS Pixel and TRT (STm voltage regulators)
Advantages
No need for remote voltage regulation
Possibility of using high current “bulk” supplies
Less cables and cheaper
Disadvantages
Additional drop (lower efficiency & extra cooling)
Less control of the return currents
A few details on ATLAS TRT and CMS ECAL
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
9
ATLAS TRT
Vcc, Vee & RTN
Type II cables
(6 - 15 m)
Front-end
Boards
Patch Panel 2
Type III cables
(40 - 60 m)
Maraton
DC-DC
Converters
Type IV cables
(40 - 60 m)
(Voltage Regulators)
Vcc, Vee & RTN
Vdd & RTN
Feed 1/32 of the detector
6 outputs for Wheels A
8 outputs for Wheels B
8 outputs for Barrel
Vcc, Vee & RTN
Front-end
Boards
Vdd & RTN
6 or 8 FE units
30 or 48 cables
(6 - 15 m)
380V DC & RTN
AC-DC
Control
Vdd & RTN
5 cables
(40 - 60 m)
Experimental Cavern
(UX15)
Control Room
(USA15)
Very similar to ATLAS Pixel
Few PS units
Digital and Analog return
currents separated
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
10
ATLAS TRT: Voltage Drops
Vcc, Vee & RTN
Type II cables
(6 - 15 m)
Front-end
Boards
Patch Panel 2
Type III cables
(40 - 60 m)
Maraton
DC-DC
Converters
Type IV cables
(40 - 60 m)
(Voltage Regulators)
380V DC & RTN
Vcc, Vee & RTN
Vdd & RTN
Feed 1/32 of the detector
6 outputs for Wheels A
8 outputs for Wheels B
8 outputs for Barrel
Vcc, Vee & RTN
Front-end
Boards
Vdd & RTN
6 or 8 FE units
30 or 48 cables
(6 - 15 m)
Control
Vdd & RTN
5 cables
(40 - 60 m)
Experimental Cavern
(UX15)
Element
Type III cables
Voltage Regulators
Type II cables
Maximum drop
AC-DC
Control Room
(USA15)
Drop
0.5 – 1 V
0.8 – 1.5 V
0.5 – 1.3 V
3.8 V
6.3 V at the source for getting 2.5 V on the front-end
40 % efficiency (30% if AC/DC and type IV cables included)
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
11
CMS ECAL
812 DC-DC converters
Drop in the regulators: 1.8 V
Power loss: ~80 kW (46 kA * 1.8 V)
~60% efficiency in-detector
Overall efficiency ~30%
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
12
Can it be used for SLHC?
Voltage regulators remotely located
Amount of cables entering the detector volume is not easily
reduced
Large current  high power loss
Voltage regulators on the load
Better power yield
Preferable very low drop VR, low current
Drawback: additional power dissipation in the detector
volume
If Vdd is 1 – 1.3 V even low drop VR will add at least 10-20%
of power
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
13
ATLAS LARG Calorimeter
Use of DC-DC converters
58 PS units delivering up
to 4 kW
27 DC-DC in one unit
7 Voltages
Redundant scheme
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
14
DC-DC Converters
ATLAS Tile calorimeter also using this
scheme
Advantages
High efficiency (>80%)
Small cable volume to deliver high power
280V DC  4 – 11 V DC ; ratio 25 – 70
Disadvantages
Very long development time to get a
radiation (and low magnetic field) tolerant
design
Complex devices not easy to produce
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
15
Can it be used for SLHC?
Very attractive to reduce the volume of services
Same drawback as the VR concerning additional
power dissipation in the detector volume
Need for high efficiency
Complex devices when radiation hardness is needed
Better to start development early on not too many variants
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
16
Conclusion
Several schemes used for the current detectors
Individual PS remotely located
VR close to the load or a bit remote
DC-DC converters
Only very low drop VR and DC-DC converters could
be used for SLHC
At the cost of more power in the detector volume
Because of our environment such devices will
require a lot of development
Ph. Farthouat
Common ATLAS-CMS Electronics Workshop for SLHC 19-21 March 2007
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